Field
This disclosure relates to printing and encoding labels having an embedded RFID (radio frequency identification) transponder.
Description of the Related Art
Radio-frequency identification is a wireless, noncontact method for automatically identifying and tracking tags attached to objects ranging from railroad cars to retail merchandise to livestock. A common type of RFID tag contains an antenna and a transponder integrated circuit chip, but not a battery or other power source. Such RIFD tags receive and store energy from an interrogating radio signal and then transmit a response powered by the stored energy. The response includes identifying information retrieved from a nonvolatile memory within the transponder integrated circuit chip.
The nonvolatile memory within an RFID transponder integrated circuit chip typically includes a 96-bit EPC (electronic product code) memory and optionally may include a user memory. Not all RFID transponder integrated circuit chips include a user memory. The user memory, if present, may store up to 8 kilobits. A typical size for a user memory is 512 bits.
An RFID tag must be encoded before it can be used, which is to say the appropriate identifying information must be stored in the nonvolatile memory within the transponder integrated circuit chip. Some RFID tags may be encoded during manufacture. Other tags may be encoded using a radio frequency transmitter that transmits the data to be stored in the nonvolatile memory and provides energy to the tag during programming.
An RFID label is a printable label with an embedded RFID transponder integrated circuit chip and antenna. Typically such labels include an adhesive backing covered by a releasable liner. When the releasable liner is removed, the adhesive backing may be used to affix the label to an object. An RFID label printer is used to print text and graphical information, such as a bar code, on the front of the label using direct thermal printing, thermal transfer printing, ink jet printing, or some other printing method. The RFID label printer contains a radio frequency transmitter to encode the transponder integrated circuit chip. The RFID label printer may also contain a receiver such that the information stored in the transponder integrated circuit chip may be read back to verify successful encoding.
Throughout this description, elements appearing in figures are assigned three-digit reference designators, where the most significant digit is the figure number where the element is introduced. An element that is not described in conjunction with a figure may be presumed to have the same characteristics and function as a previously-described element having the same reference designator.